Photosynthesis is one of the most essential reactions on Earth and is a scientific area that is the topic of several research projects. The purpose of this book is to present the basic aspects of photosynthesis, and the outcomes collected from various research groups. It comprises of major topics like the path of carbon in photosynthesis, and special topics in photosynthesis. Important sub-topics of these subjects such as the path of carbon in photosynthesis, high-CO2 response mechanisms in microalgae and role of C to N balance in the regulation of photosynthetic process have been broadly discussed and analyzed by experts in the book.